This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. IspG is a protein of 41 kD, known to play a key role as a catalyst in the engineering production of host organisms for biofuel production. According to the research results of Liu and his coworkers, IspG is present as mutli-protein-complexes. Because IspG catalyses reductive deoxygenation reactions, their partner proteins are either involved in electron transfer or related to the regulation of IspG reduction potential. To have a better understanding of the mechanism and improve the IspG activity, we have undeertaken the identification of these proteins by mass spectrometry. In-gel digestion of each of these partners followed by analysis by MALDI-TOF MS and nanoLC-MS/MS on LTQ-Orbitrap (Thermo-Fisher) are being performed to identify these partners.